HMR-1556

Biochem/physiol Actions

HMR-1556 is a potent and selective blocker of the heteromeric KCNQ1-KCNE1 (KvLQT1-MinK) voltage-gated channel-mediated slowly activating K+ current (IKs IC50 = 120 nM in hKCNE1-transfected Xenopus oocytes; little or no inhibition of Herg, Kv1.3 (KCNA3), Kv1.5 (KCNA5), Kir2.1 (KCNJ2), HCN2 (BCNG2) current in respective oocyte transfectants). HMR-1556 is more potent than chromanol 293B (IKs IC50 = 34 nM and 2.1 µM, respectively; guinea pig ventricular myocytes), being inefficient against L-type Ca2+ channel or rapidly delayed & inward rectifier currents (IKr & IK1) in guinea pig ventricular myocytes, nor transient & sustained outward currents, I(to) & I(sus), in rat ventricular myocytes.